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Ngu^nThiMayvaO/g Tgp chi KHOA HQC & CONG NGHE 126(12) 181 187 TAI BIEN T R i r O T L d D A T Of TINH CAO BANG NGUYEN NHAN VA GlAl P H A P PHONG T R A N H , G I A M NHE Nguyin Thj Mdy''''*, Trin Viet Khan[.]
Ngu^nThiMayvaO/g Tgp chi KHOA HQC & CONG NGHE 126(12): 181 - 187 TAI BIEN T R i r O T L d D A T Of TINH CAO BANG NGUYEN NHAN VA G l A l P H A P P H O N G T R A N H , G I A M N H E Nguyin Thj Mdy'*, Trin Viet Khanh\ Ta Thj-Tho' 'Trudng Dai hgc Suphgm - DH Thdi Nguyen ^Dgi hoc That Ng T6M TAT Trong miy th|p ky gan day, trugt Id dit Id mft dgng tai bien ty nhiSn xay tuong ddi ph biin d viing doi niii Viet Nam Dac bift dgc theo cdc tuyen duong mdi dugc xay dyng, cac tuylii dudng dang dugc md r^ng ho^c nin thing Cdc khu dan cu tap trung dudi chdn sudn d6c va dpc cdc bd sdng, sufli Hau qud cua trugt Id dSt din din vdi lip dudng giao thong, de dga cu6c sing ciia cac khu dan dnh hudng tdi sinh hogt cung nhu ddi sing vgt chat, tinh than cua bd noi day Tfr khda: tai biin, trtrgt Id ddt, hiin trgng, hdu qud, nguyen nhdn gidi phdp MO DAU Cao Bang Id mgt tinh mien nui bien gidi thufc Ddng Bic Bg Dia hinh chu yeu ggm cdc nui trung binh va nui thap cd dg cao tu 300 den gin 2000 m, bj phan di, chia cdt vd chju tdc dgng mgnh me bdi tai bifn trugt Id dat Hang nam, vdo miia mua, trugt Id dat xay khd phd bien tren nhiing khu vyc cd dia hinh ddc Trugt Id da phd huy va lam hu hai nhilu ngdi nhd dan, cdc cdng trinh cdng cgng va thyc su khdng chi thift hgi vf kinh tf md gdy hoang mang lo sg nhan dan Dl gidm thieu tdt nhat cac tai bien nay, chffng tdi tifn hdnh nghifn cmi tim hilu vl nguyen nhan, CO chf xuat hifn, dy bao, khoanh vung boat dgng tai biin va tu dd d l xuit nhung giai phap xu ly kip thdi vd phdng tranh cd hifu qua K H A I N I E M V E T R U O T LCJ Trugt Id Id mgt dang tai bifn dja chit phd bifn d cac tinh miln ntii, hien cd nhifu dinh nghTa vf trugt Id khde nhau, song cung dfu thdng nhit dinh nghTa ve trugt Id nhu sau: " Tru0 l& la qud trinh chuyen dgng cua dat dd ve phia dir&l sudn doc dual dnh huong ciia trgng luc." Neu theo quan difm vl dia mgo thi trugt Id thyc chat la qua trinh sudn dudi tac dpng cua nhieu yfu to khde nhau: ddc sudn, nudc chdy tren mat, nudc ngim, tinh chit CO ly Clia dit da, hogt dgng tan kiln tgo Cd nhilu each phdn logi trugt Id Tuy nhien, chung tdi cho ring sy phan logi trugt Id theo ' Tel 01278 262828 kieu chuyfn ddng theo "ngudn gdc"ciia cCia cdc giao su dia chdt, trudng dai hgc Michigan ciia My don gidn vd df hifu Theo each phan loai trugt Id bao gdm chu yfu cdc loai sau; Trufft: la cac vat lieu dat da dugc chuyfn ddng tff tff dudi tac ddng cffa lyc xudng dudi chdn sudn, cac vat lifu nhieu cdn giff nguyen cdu tnic (mat ldp) ban dau trudc xay trugt Trong trudng hgp khdi trugt theo mgt ddng keo dai vdi chifu ddi ldn gap nhieu lan so vdi be rgng thi dugc ggi la trugt dong Kieu trugt ddng ndy thudng xay dgc theo cdc sudi nhd va di kem vdi nd la lii bun da Phan tfch chi tift hon vf hien frgng cua cac khdi trugt chung ta cd thf cdn phdn biet dugc mdt sd phy kieu trugt khde: + Trugt theo vd phong hod, tffc la khoi trugt cd mgt trugt (guong trugt) ndm vd phong hoa hoac mgt tifp xuc giffa vd-phong hoa va mat da gdc + Trugt theo mgt ldp la khdi trugt cd mat trugt chinh theo mgt phan Idp cua dat da hogc theo mdt mat nut ciia dd Kilu truot thudng hay xdy mat ldp, mat khe nfft cua dat dd tning vdi hudng sudn Trirgt chdy: la cac vat lifu dit da chuyen dgng tu bdc dia hinh cao theo sudn ddc xudng bgc dia hinh thip hon theo mgt ddng rdi, vat lifu dugc sip xep hdn ddn, phd buy hoan toan cau true ban diu Qua trinh ndy xay thudng d noi cd vdt lifu cd kich thudc hdn dgn, kem theo giffa cdc khoi dd cffng la cac vat lifu hat set ngdm nudc hoac biin nhao 181 Nguyin Thi May vd Dig Tap chi KHOA HOC & CONG NGH$ Bd Id: la hifn tugng cdc vat lieu chuyen dgng gin nhu roi ty tff tren phin dia binh cao xudng phfa dia binh thip va bang Dilu kifn xdy dd Id la bf mat nghifng cffa mgt trugt ldn hon mat nghieng cua sudn dia hinh, hodc it nhdt sudn dia hinh cd dd ddc gan thdng dung Hdn hop: la hien tugng dien cua hai qua trinh trugt va dd Id Qua trinh xay d noi cd chiiu ddi sudn ldn, cd sy thay ddi dot ngdt ve dd ddc sudn Thyc tf, d nhieu noi, rat hilm cd thi quan sdt thiy cac khdi trugt xay rifng biet ma phan ldn la kit hgp cd hai qua hinh tren Kft qua dilu tra khao sdt hien tugng trugt Id d Cao Bdng cung phin Idn gap trudng hgp va dugc ggi chung Id trufft Id hdn hgp PHU'ONG P H A P N G H I E N CUXJ D I giai quyft cac nhifm vu vd yeu cau thyc te chung tdi dd su dyng cdc phuong phap nghifn cun va khdo sat sau: 1) Difu tra khao sat thyc dia 2) Thu thgp xff li tai lifu 3) Phan tich tdng hgp cac ket qud khao sdt de danh gid nguyfn nhdn, co che xuat hien va phgm vi anh hudng cua cac tai biin, kiln nghi giai phap phdng tranh 126(12): 181 - 187 ly ty nhien (dja hinh, dja mgo, khf tugng, thiiy van ), cac yfu td thdi gian va cac yfu to nhdn sinh (pha riing, cdc logi ngogi lyc ngudi tac dyng Ifn sudn ddc, muc dd dung din cua phuong an thiet ke, cdng nghf va tifn dg thi cdng bd ddc nhdn tao ) Anh hudng xau cua cac yeu td tren lam giam khd nang chong trugt cua khdi dat dd d sudn doc, thay ddi trgng thai ffng sudt hong khdi dat da Cac yeu td dd kit hgp dan xen vdi tgo nfn cac CO chl mit dn dinh sudn ddc khde Nhdn td dia hinh dia mgg Cao Bdng la vung cd dia hinh phffc tgp vd da dgng dugc thf hifn tren ba mifn dja hinh chu yfu: Miln dia hinh Karst, miln dja hinh mii cao, mien dia hinh nui thdp thung liing Qua kit qua thdng kf cho thdy sd lucmg cdc diem trugt Id dat da ty If thugn vdi cao vd dp ddc dia hinh Cd trfn 60% so dilm trugt Id phan bd d cac khu vyc cd cao dia hinh tu 500 din 1000 m va ddc sudn ldn hon 35° Trong cac don vi dia mgo khac nhau, dieu kifn dia hinh gay trugt Id cung khac nhau, theo kft qua nghien ciru cua df an trugt Id xay manh me nhdt d cac thung lung xam thyc, tilp theo Id cdc vung nui cao, mii trung binh vd thdp nhat la d cdc nui va cao nguyen da vdi, cdc trung cd ngudn gdc khde Nhdn to dia chdt KET QUA N G H I E N CUTJ Nguyin nhdn vd nhdn to dnh hu&ng Nhu da biet, nguyen nhdn gay trugt cd the hogc la do ben cua dat da bj giam di, hogc la trgng thai ung suit d sudn ddc bi thay ddi, hoac cd hai nguyfn nhdn hfn lam cho difu kifn cdn bang ciia khdi ddt dd d sudn doc bj phd buy Cac yiu td anh hudng Id todn bg nhiing yeu td ty nhifn va nhan tao cd tac dyng hd trg cho qud trinh phd hogi sy can bang cua khdi ddt da xdy dugc df dang Tropg nhffng trudng hgp thudng gdp nhit cac yfu td nay cd thf bao gdm cac yfu td ty nhien, nhu dgc diem dja chat (dja ting, kiln tao, diit gay, nfft ne, chi tifu co ly cua dit da, ddc diem nudc dudi dat, cdc qud trinh va hifn tugng dia chat dgng lyc cdng trinh ), cdc dilu kifn dja 182 Ddc dilm thgch hgc vd vd phong hod ciia viing la nguyfn nhan dja chat chinh lien quan dfn tifm nang phat sinh trugt Id dat dd va chffng cd moi lien quan khd chdt che vdi Ket qua khdo sat cho thiy cac thdnh tao trim tich luc nguyfn tudi Paleozoi va Mesozoi vung phdn bd trfn difn rdng, dd san pham phong hoa tff ddt da cd phin cat kit, thach anh, da phifn set, da philn set vdi tudi Paleozoi (thugc cdc hf ting Thin Sa, Luge Khieu, Mia Le, Nd Qudn va Tdc Tdt) df tham gia vdo qua trinh ttWttt id dit Trong thyc te, thdnh phin khodng ,v,at ciia nhdm dd ndy Id set sericit bj nen ep, phan ldp mdng, mat phan ldp nhieu noi trung vdi mgt doc dja hinh, vd phong boa cua chung chu yiu Ngu,, ^^h\M&yvdDig Tgp chi KHOA HOC & CONG NGHE Id vyn thd nen khd nang frugt Id dit da rit cao va xuit hien dgc cac myf n tinh If 206, 207, 208,211 vd dogn nam deo Gid trfn Qudc lg Nhdn Id dg ddc sican Cao Bang la vffng cd dia hinh phffc tap, bj phdn cit mgnh Phin ldn dien tfch cua Cao Bdng la cac mii da vdi tao thdnh cdc day niif hogc tiing khdi nui ddc lap phan bd chu yeu d phia ddng Nhung vung dia hinh thodi, vdi df doc